In an era of dentistry driven by high esthetic demands and standards, flapless post-extraction dental implant placement with hard and soft tissue loss can pose a considerable aesthetic, surgical, and/or restorative challenge. In vivo studies have reported that dental implants placed into post-extraction sockets do not alter the wound healing and remodeling process of the socket nor preserve the labial bone plate especially in the anterior region of the mouth where the labial bone plate is approximately 0.5-1.0 millimeters in thickness post tooth extraction. Dental implants that are too wide in diameter that completely fill the extraction socket or that are placed too close to the labial bone plate will result in loss of labial bone subsequent to remodeling. This dimensional change can lead to ridge collapse, thinning of the peri-implant soft tissues, and gingival tissue discoloration due to labial bone plate loss. It is important to consider proper hard and soft tissue management when managing flapless post-extraction dental implants in the aesthetic zone.
Several clinical procedures have been proposed to assist in addressing the disadvantages associated with flapless post-extraction dental implant placement and tissue loss. In vivo studies have shown that dental implant position and diameter play a significant role in maintaining the labial bone plate height with full osseointegration, without the aid of a bone or hard tissue graft. The former strategy being palatal dental implant positioning within the extraction socket and ‘gap distance’ between the facial surface of the dental implant and residual labial plate thereby allowing a blood clot to fill the gap and organize into granulation tissue predetermined to form new bone. The latter strategy uses smaller diameter dental implants in order to create a favorable gap distance for the labial blood clot. Thus, new labial bone plate formation may be achieved by the use of smaller diameter dental implants placed in a palatal position within the extraction socket.
The labial bone plate can collapse about 1.0 millimeter even though osseointegration can be achieved. Minimizing labial bone plate collapse is important to achieve satisfactory aesthetics. Studies have shown that bone grafting the gap can limit the amount of ridge shape change both clinically and on cone beam computer tomography (CBCT) to 0.1 millimeters. Xenografts and allografts have been analyzed in these studies. Therefore, it is of clinical significance to maintain a gap distance after dental implant placement for not only blood clot formation but also bone graft placement to maximize outcomes of dental implants placed into post-extraction sockets. The bone material acts as a filler or scaffold to maintain the volume of the blood clot for new bone formation.
One problem with using smaller diameter dental implants is that they can result in decreased primary stability of the dental implant since the lateral surrounding walls of the extraction socket are rarely engaged in total, nor should they be due to the aforementioned socket remodeling. Primary stability of dental implants in extractions socket should achieve a minimum of 25 Newton-Centimeters (Ncm) of insertion torque to reach 96% survival rate. One technique to achieve adequate primary stability (e.g., >25 Ncm) is engaging the apical-palatal bone beneath the floor of the nose anatomically, with smaller diameter dental implants. Thus, longer dental implant lengths are required (e.g., 15 millimeters) to obtain satisfactory primary stability, though using such longer dental implant increases the risk of perforating the base/floor of the nose. Another strategy in achieving adequate initial primary stability in extraction sockets is using a wider diameter implant with the trade-off being a decreased gap distance between the dental implant and labial bone plate.
Prior dental implant designs typically include threaded or screw shapes with a tapered body from coronal to apical; the coronal aspect of the dental implant head being wider at the top versus a more narrow diameter at the base or lowermost end of the dental implant. This typical design mimics the natural extraction socket in the patient's mouth in shape and form. Anatomically, the apical area of the extraction socket has thicker labial bone and coronally the labial bone is thinner. As the apical region of typical tapered dental implants is smaller in diameter (e.g., as compared with the coronal region of typical dental implants), the apical region may not offer enough surface area to achieve adequate primary stability when installed, especially when using a surgical strategy involving a decreased dental implant length for fear of perforating the base/floor of the nose. In addition, typical tapered dental implants are wider at the top (e.g., coronally) thereby decreasing the gap distance between the upper neck of the dental implant and the extraction socket. Consequently, wider diameter tapered dental implants are typically used to increase dental implant primary stability (e.g., a 5 millimeter dental implant might be used instead of a 4 millimeter dental implant), thereby decreasing the labial gap distance and thus impeding subsequent blood clot formation with bone grafting, which is ideal for forming new labial bone plate between the dental implant and the extraction socket.
Another factor in dental implant design relative to dental implant placement is that with typical tapered dental implants being wider at the top, this negatively impacts palatal placement. As the dental implant is placed and driven into the extraction socket apically, the wider neck may engage the palatal bone plate and may bounce/move or angulate the dental implant more to the facial aspect of the extraction socket. This can result in undesirable labial placement and angulation of the dental implant and potentially a decreased gap distance between the dental implant and the facial aspect/side of the extraction socket.
Another factor in dental implant design is dental implant position relative to adjacent teeth or adjacent dental implants. Some studies have shown that close proximity of adjacent dental implants can cause interproximal attachment (e.g., of hard and/or soft tissue) or papilla loss and consequently cause black interdental triangles between teeth and/or dental implants.
Some previous dental implants have attempted to provide a segmented non-continuous gap between the coronal portion of the dental implant and the osteotomy site or extraction socket by eliminating a side portion of the dental implant making a flat cutout or cutaway portion. However, during installation, such dental implants must be installed with a specific rotational position relative to the socket such that the flat cutout is aligned with, for example, the buccal bone plate in the mouth of the patient. Otherwise the dental implant will not promote bone growth in the desired location.
Thus, a need exists for dental implants with relatively wider apical portions to increase primary stability of the dental implant while promoting bone growth in desired locations, but without requiring rotational-orientation restrictions during installation. The present disclosure is directed to solving these problems and addressing other needs.